What is pink salt and from where we can buy it?

Wait before you buy pink salt! Are you using pink salt for preserving, like bacon, or are you using a "gourmet" salt, like himalayan, hawaiian, or grey sea salt. They are very different. If using for preserving I usually buy it from a butcher (like The Fatted Calf) a spice shop, or online.

This doesn't tell you where to get it, but it's a nice primer on various salts: http://food52.com/blog/3377-10-salts-to-know

I buy the pink salt from Murray River in Australia at Whole Foods. Check in the Cheese section.

Do you mean the kind of pink salt that is used for curing?

I have seen a pink salt that comes from the Himilaya Mountains. You might be able to find it at a well-stocked grocery store like Whole Foods. If you can't find it, just substitute it with another salt. The Himilayan salt I have seen is often a coarser grain, but I have also seen fine-grained as well.